Snap gauge



May l0, 1949. s` SUBBER` 2469,613

SNAP GAUGE Filed June 3, 1944 lNVENTOR Patented May 10,/ 1949 UNITED- srAT-as PATENT orales SNAP GAUGE Leonard Saul/ Sablier, Upper' Darby, Pa.

ApplcationiJuneiS, 1944-, Serial-No.153868 (C l. 33e-147i) 13 Claims. l',

My invention relates to measuring, appflalills for accurately determining. linear size, relationships, such. asdiameters 0r distances. between plane surfaces. or surfaces of' revolution,` with respect to a, standard part. or dimension, andl is herein shown as` embodied in. an. externalv gage for measuring` rectangular surfaces. or surfaces of' revolution...

it. is customary while machining articles. such as machine parts,- tor theoperator to stopI the machine.- and. apply. a measuring device-,either fixed., adjustable, limitV or indicating-to deter.- mine how tar theA operation has progressed.L In many cases, due. to. the nature of themeasuring device or gage, measurements must bev taken. irr-` diieotly,. thereby introducing additional errors. In most cases, evens though the measurementcan be taken. directly withoutremoving the partirom the machine., the measurernent.l is. inaccurate and cannot be dupucatea even.v bly- 'skiue'd operators. There-fore, one. o-bjeot. of my invention. is. to pro.- videa simple compact,.,comparativel.y inexpensive apparatus. which can. ibo. used by different. in.- dividuals such.v as. an operator at a. machinev or by an. inspector at some other location toiobtain duplicate measurements..

Another object of my invention is toprovide a device which requires. littleor noskill: iso-operate.

Another object. of my invention is to. provide an. instrument is. Seli-locating. withY `respect to. the. Work. part.

Another object. of. my invention isl toprovide a gage which. Will. measure` equally Well at an unobstructed portion. of the worl andy also directfly adjacent to common obstructions such as shoulders or flanges..

Another obiect of invention is to provide a gage which will measure. .directly iniplaces usually considered inaccessible such as. undercuts provided for tool reliefY or recesseslike ring l grooves in pistons..

Another object of my invention is to: provide a device which can bey used t0 measure directly work parts. While the parts are. in.A the machine, the. device being. so proportionedthat it' will' clear the usual obstacles: foundy on. machines suol-1. as holding devices, xtures. and wheel guards.

Another obje'ctof. my invention is` toprovide a gage which can be held in a suitable stand for use as a bench comparator when the nature of the work indicates that. the work should. be presentedlto-.thegage Another object. ot invention is to. provide a gage which! can be. adjusted, and. setto take measurements. at. predeterminedl locations. on

irregular surfaces.. An. example of this. isr the checkingof theV chordal Width. of an involute gear tooth.

Another object of my invention. is-v to provide a gage, of suchsize and proportionsy that several gages, cani be grouped. closely in. suitable holding meansV for simultaneously cllieclring.l a plurality of. dimensions. such as diameters, shoulder lengths and..concentrici'ty.`

Another object of my. invention. is to DlOvi'de a gage so designed that in many instances measurements can be taken While the WorkM part is. in. motion., as.' for instance, measuring a shaft diameter or a. flange Width. Witliogut stoppingv the machine..

Another object. of my invention is to provide a'. gag-e,y the accuracy of which. is not affected by room temperature or .the temperature of the operatorshand Another object of. my inventionyis toA provide a gage,` the operation and. accuracy of which.. is not. alectedby normally ypresent amounts` of cutting uids, lubricants, grit. dirt. and. other foreign matter.

Another object of. my invention. is to provide a gage thatl will notbe damaged nor its accuracy impaired. impact or vibration. which `norn'fially would be expected'y in sl1'0puse.

Another object.v of my invention is to provide a gage so designed. that it canbe adapted? readijly to. special or unusual. jobs. by the addition of standard accessories Which can be, clamped. on or removed rapidly Without modifying or changing the gage in any way or impairing its. usefulness.

Examples of. measurements. made using accesseries are. checkin-g. leadferror, pitchdiameter and drunkenness of screw threads.; and checking strain instructures by. m easuring elongation due to load.

. Other objects. and. advantagesv of my, invention will be apparent from the following. description, the appended; claims,I and the accompanying drawing, in. vvfliichV Fig.. lis a` side, elevation of. a. measuring device embodying. the. present, invention.; Fig` 2', a schematic. diagram illustrating the method of. ob,.-

taining. movement Without' friotion; Fig.. 3, a horizontal section. on the. line 3`-3, Fig. 1i; and Fig. 4 a horizontal.. sectionon-. the. line. 4.-.-41 ig..

Similar numerals refer to similar parts throughout the several views.

Thev L.,shaped.frame member I,. made ot one or more parts, is provided Withan. upper gaging anvil ,2 suitably attached..y rIfhe lower jaw. .3 oarriesthelower gagingI anvil 4.

Fig. 3 shows the preferred method of adjustably attaching lower jaw 3 to the control member 5 so that members 3 and 5 move as an shaped unit. The lower jaw S is retained in correct juxtaposition to control member 5 by means oi screw 'I which engages nut d which in turn clamps against the dovetail 5 on the control member 5 locking the lower jaw 3 and control member 5 together.

The control member 5 is attached to the frame member I by means of two flat springs or reeds 9 and Ill the L-shaped frame member I and the movable L-shaped unit together forming a generally U-shaped body or frame in which one of the anvil-carrying arms is adjustable to-and-iro relative to the other arm. The upper reed is fastened at one end to control member 5 by suitable means such as screw Il. The other end of reed 9 is attached to the frame i by suitable means such as screw I2. One end of the lower reed le is fastened to the control member 5 by suitable means such as screw I3, while the other end oi reed l0 is attached to the frame I by a suitable fastening device such as screw Ill.

Fig. 2 illustrates schematically 'the relative movement between the reeds and the control member which act, in effect, like e. Z-shaped linkage wherein the inner ends of the reeds overlap and are fastened to the member 5 and extend outwardly therefrom in opposite directions to their respective points oi attachment to the L-shaped frame member i. The upper reed 9 pivots about screw I2 when the control member 5 is forced downward relative to the frame member I by placing a part to be inspected between the gaging anvils 2 and il, assuming the position indicated by 9. At the same time, the lower reed Ill pivots about screw iii, assuming the position indicated by Iii', while the control member 5 assumes the position indicated by 5. Suitable means, such as the spacer I5, are provided for maintaining the correct angular generally non-parallel relationship between the upper and lower reeds 9 and I9.

Since the reeds are so proportioned and aligned that the control member 5 remains substantially parallel to the vertical leg of the frame member I while moving vertically, the anvils 2 and i remain substantially parallel to each other throughout their range of travel.

Moreover, since the control member 5 does not touch the frame member i, nor slide against it, movement of the control member 5 relative to the frame member I is obtained without friction or lost motion. Furthermore, normal expansion and contraction of the frame member I produces no measurable error of measurement.

Fixed measuring pressure is provided by a lowgradient spring i@ which urges anvil l toward anvil 2 by exerting an upward thrust against the control member 5.

The backstop Il, which is a sliding fit in the i control member 5, is provided to properly locate the part being measured between the anvils 2 and 4. It is locked in the control member against rotation and axial movement, by suitable means indicated at I8. The backstop I1 extends into a clearance hole in the frame member I which limits the travel of the control member 5, preventing damage to the reeds 9 and Iii and spring I6.

The handle I9 is made of suitable material to provide proper balance and to insulate instrument from the heat of the operators hand.

A suitable indicating mechanism 2c, such as a dial indicator; or a pneumatic, hydraulic, or electrical gage-is mounted in the frame member I in such a manner that it can rotated, through an arc of 360 degrees, to the most convenient position. for observation or to clear obstacles. Fig. 4 shows the preferred method of locking the indicator 2li in the desired position. The screw 2l passes through the collar 22 and engages the nut 23. Both the collar and the nut 23, which are machined to nt the of the indicator 2li, are free to slide in the frame men ber I. Tightening screw 2i causes the collar i2 and the nut 23 to bind against the indicator 35 and the frame member I.

The indicator 29 is actuated by the screw Ii which transmits the vertical movement oi the lower jaw 3 through the control member Since the insertion of a part to be measured between the anvils 2 and l moves the actuating screw Ii away from the indicator rapid insertion will not damage the indicator 2i).

The distance between the anvils 2 and 4 is substantially the same as the exposed length of the control member 5. Therefore, the measurement taken by the instrument is controlled by the length of the control member 5. By making the control member 5 of a material having the proper thermal coefficient of linear expansion, the measuring device can be made to compensate automatically for room temperature changes, for a specied material to be measured. When materials with different coefficients of expansion are to be measured, suitable control members 5, with proper rates of expansion can be quickly and easily substituted.

The overlap mounting of the leafs 9 and I0 upon the member 5, to form Z-shaped linkage, as described hereinabove, provides greater stability for the member 5 than would be the case if the two mountings were in vertical alignment and thereby minimizes wobbling or tilting of the lower jaw 3 and the anvil I. This mounting also facilitates the quick interchange or substitution of control members having different coeiiicients of expansion as explained above and permits proportioning of the gauge so as to accomplish the objectives set forth herein.

While the form of apparatus herein described constitutes a preferred embodiment of my invention, it is to be understood that the invention is not limited to this precise form, and that changes may be made therein without departing from the scope of the invention which is deined in the appended claims.

I claim:

l. A measuring device comprising a frame member, a fixed work-engaging element carried by said frame member, a second work-engaging element, and means movably mounting said second element upon said frame member so as to permit said second element to move to-and-fro substantially perpendicularly relative to said fixed element, said means including a base upon which said second element is mounted, said base extending generally perpendicularly from said second element toward said xed element, and a pair of oppositely-directed leaf springs connected to the ends of said base and fastened to said frame member.

2. A measuring device comprising a frame member, a xed upper work-engaging jaw carried by said frame member, a lower work-engaging jaw, and means movably mounting said lower jaw upon said frame member so as to permit said lower jaw to move substantially vertically toand-fro relative to said upper jaw, said mounting means including a generally -vertical base upon which saidv lower jaw is mounted and a pair of leaf springs connecting the top and bottom respectively of said base to said frame member, said leaf springs being connected to said base at generally diagonally-related points and extending oppositely therefrom generally Z-wise and being connected at the other ends to said frame member at laterally-spaced points, the accuracy of measurements taken by said device being substantially independent of and unaffected by expansion and contraction of said frame member.

3. A measuring device comprising a frame member, a fixed upper work-engaging jaw carried by said frame member, a lower work-engaging jaw, and means movably mounting said lower jaw upon said frame member so as to permit said lower jaw to move substantially vertically to-andfro relative to said upper jaw, said mounting means including a generally vertical base upon which said lower jaw is mounted and a pair of generally non-parallel leaf springs connecting the top and bottom respectively of said base to said frame member, said leaf springs being connected to said base at generally diagonally-related points and extending oppositely therefrom generally Z-wise and being connected at the other ends to said frame member at laterally-spaced points, said base being constructed and arranged for quick attachability and detachability, by means of two fasteners thereby to permit interchange of a plurality of bases having dierent co-efiicients of linear expansion.

4. A measuring device comprising a frame member, a xed upper work-engaging jaw carried by said frame member, a lower work-engaging jaw, and means movably mounting said lower jaw upon said frame member so as to permit said lower jaw to move substantially vertically to-andfro relative to said upper jaw, said mounting means including a generally vertical member disposed adjacent said frame member, a pair of leaf springs connecting the top and bottom respectively of said vertical member to said frame member, said leaf springs being connected at one end to generally diagonally-related points on said vertical member and extending generally Z-wise therefrom and being connected at the other ends to laterally-spaced points on said frame member, and a slide and lock connecting said lower jaw to said vertical member so as to permit vertical adjustment of said lower jaw along said vertical member thereby to vary the clearance intermediate said upper and lower jaw,

5. A measuring device comprising a frame member, a xed upper work-engaging jaw carried by said frame member, a lower workengag ing jaw, means movably mounting said lower jaw upon said frame member so as to permit said lower jaw to move substantially vertically toand-fro relative to said upper jaw, said mounting means including a generally vertical member disposed adjacent said frame member, a pair of leaf springs connecting the top and bottom respectively of said vertical member to said frame member, said leaf springs being connected at one end to generally diagonally-related points on said vertical member and extending generally Z-wise therefrom and being connected at the other ends to laterally-spaced points on said frame member, and including means connecting said lower jaw to said vertical member, and a work-backstop carried by said vertical member and extending into an oversize hole in said frame member, said-work-backstopthereby serving to limit the movement of said vertical member relative to said frame member.

6. A measuring device comprising a frame member, a fixed upper work-engaging jaw earried by said frame member, a movable lower work-engaging jaw, a generally vertical member disposed adjacent said framemember, a pair of leaf springs connecting the top and bottom respectively of said vertical member to said frame member, said leaf springs being .connected at one end to generally diagonally-related points on said vertical member an-d extending generally Z-wise therefrom and being connected at the other ends to laterally-spaced points on said frame member so as to permit said vertical member to move substantially vertically to-and-fro relative to said upper jaw,a slideand lock connecting said lower jaw to said vertical member so as to permit vertical adjustment of said lower jaw along said vertical member thereby tovary thevclearance intermediate said upper and lower jaws, and a diagonally-adjustable work-backstop adapted to contact the work at a point 90 degrees between said upper and lower jaws regardless of the work-diameter, said work back-stop being carried by said vertical member and extending into an oversize hole in said frame member, said work-backstop thereby serving to limit the movement of said vertical member relative to said frame member.

7. A measuring device comprising a generally U-shaped frame made up of an upper inverted L-shaped member and a lower upright L-shaped member, the vertical arms of said L-shaped members being generally parallel with a clearance therebetween, the horizontal arm of said upper member providing an upper work-contacting jaw, the horizontal arm of said lower member providing a lower work-contacting jaw, the

work contacting jaw of the lower L-shaped member being adjustably mounted on its vertical member, said lower L-shaped member being .movably mounted on said upper L-shaped member by means of a Z-shaped linkage formed by the lower vertical member and substantially horizontal flexible reeds, said reeds being attached to both L.shaped members, said linkage imparting substantially parallel relative movement between the upper and lower jaws, and indicating mechanism mounted upon said upper member and constructed and arranged to indicate relative movement of said lower member, said lower member being adapted to move away from said indicating mechanism upon increase in size of the work thereby to protect said indicating mechanism from shock.

8. A measuring device comprising a generally U-shaped frame made up of an upper inverted L-shaped member and a lower upright L-shaped member, the vertical arms of said L-shaped members being generally parallel with a clear-` ance therebetween, the horizontal arm of said upper member providing an upper work-contacting jaw, the horizontal arm of said lower mem ber providing a lower work-contacting jaw, means movably mounting said lower L-shaped member upon said upper L-shaped member, said mounting means being constructed and arranged to permit the lower jaw to move substantially vertically relative to said upper jaw by means of a Z-shaped linkage formed by the vertical arm of the lower L-shaped member and substantially horizontal flexible reeds aixed thereto, said reeds being attached also, at their extremities, to the upper L-shaped member, and indicating mechanism mounted upon said upper member and constructed and arranged to indicate movement of said lower member relative to said upper member.

9. A measuring device comprising a generally U-shaped :frame made up of an upper inverted L-shaped member and a lower upright L-shaped member, the vertical arms oi said L-shaped members being generally parallel with a clearance therebetween, the horizontal arm of said upper member providing an upper work-contacting jaw, the horizontal arm oi' said lower member providing a lower work-contacting jaw, means movably mounting said lower l.shaped member upon said upper L-shaped member, said mounting means being constructed and arranged to permit the lower jaw to move substantially vertically relative to said upper jaw, said mounting means including an upper leai` spring connecting the top of the vertical arm oi the lower L-shaped member to the horizontal arm of the r upper L-shaped member and a lower leaf spring connecting the bottom of the vertical arm of said lower L-shaped member to the bottom of t'ne vertical arm of said upper L-shaped member, and indicating mechanism mounted upon said upper member and constructed and arranged to indicate movement of said lower member relative to the upper member.

10. A measuring device comprising a generally U-shaped frame made up of an upper inverted L-shaped member and a lower upright L.s'naped member, the vertical arms of said L-shaped members being generally parallel with a slight clearance therebetween, the horizontal arm oi said upper member providing an upper workcontacting jaw, the horizontal arm of said lower member providing a lower work-contacting jaw, means movably mounting said lower L-shaped member upon said upper L-snaped member, said mounting means being constructed and arranged to permit the lower jaw to move substantially vertically relative to said upper jaw, said mounting means including an upper leaf spring connecting the top of the vertical arm of the lower L-shaped member to the horizontal arm of the upper L-shaped member and a lower leaf spring connecting the bottom of the vertical arm or said lower L-shaped member to the bottom of the vertical arm of said upper L-shaped member, said leaf springs being connected at generally diagonally-related points on the vertical arm of said lower L-shaped member and extending Z-wise therefrom to their points of attachment to said upper L-shaped member, and an indicating gauge mounted upon the top of said upper L-shaped member and constructed and arranged to indicate movement of the lower L-shaped member relative to the upper L.shaped member.

11. A measuring device comprising a fixed work-contacting jaw, a second work-contacting jaw, and connecting means intermediate said jaws constructed and arranged to permit generally perpendicular movement of said second jaw relative to the fixed jaw, said means consisting of a pair of oppositely extending leaf springs, one pair of opposite extremities of the leaf springs being attached to one of the said jaws, the other pair of opposite extremities being attached to the other jaw to form a generally Z-shaped linkage.

12. A measuring device comprising a xed work-contacting jaw, a second work-contacting jaw arranged generally parallel to the xed jaw, and connecting means intermediate said jaws constructed and arranged to permit such movement or" said second jaw relative to the fixed jaw as to maintain their general parallelism, said means including a generally Z-shaped spring linkage having a pair of spaced oppositely-extending generally non-parallel leaf springs, means connecting the outer ends or" said leaf springs to said iixed jaw, and means connecting the inner ends oi said leaf springs to said second Jaw.

13. A measuring device comprising a generally U-shaped frame made up of an upper inverted L-shaped member and a lower upright L-shaped member, the vertical arms of said L-shaped members being generally parallel and having a clearance therebetween, the horizontal arm of said upper member providing an upper workcontacting jaw, the horizontal arm of said lower member providing a lower work-contacting jaw, said lower L-shaped member operably attached to said upper member by means of oppositelyextending flexible reeds attached at their extremities to the upper and lower members to form a Z-shaped linkage which imparts substantially parallel relative movement between the members, a work-backstop carried by the vertical arm of said lower L-shaped member and extending into an oversize hole in the vertical arm oi said upper L-shaped member, said workbackstop thereby limiting the movement of said lower L-shaped member relative to said upper l shaped member, and indicating mechanism mounted upon said upper member and constructed and arranged to indicate movement of said lower member relative to said upper member.

LEONARD SAUL SUBBER.

CES CITED The following references are of record in the file of this patent:

UNTED STATES PATENTS Number Name Date 361,056 Emery Apr. 12, 1887 1,253,426 Mackintosh Mar. 5, 1918 1,629,480 Darlington May 24, 1927 1,664,583 Wheelock Apr. 3, 1928 1,821,398 Simpson Sept. 1, 1931 1,879,559 Smart Sept. 27, 1932 2,190,306 Balsiger Feb. 13, 1940 2,197,198 Street Apr. 16, 1940 2,216,795 Aller Oct. 8, 1940 2,240,184 Hathaway Apr. 29, 1941 

